1. Field of the Invention
The present invention relates to a creation method of charged particle beam data, a conversion method of charged particle beam data, and a writing method of a charged particle beam, and more particularly, to a creation method of writing data used in an electron beam pattern writing apparatus and a conversion method of writing data processed in the electron beam pattern writing apparatus.
2. Description of Related Art
Microlithography technology which forwards miniaturization of semiconductor devices is extremely important, because only this process performs forming a pattern in semiconductor manufacturing processes. In recent years, circuit line widths used when writing a desired pattern on semiconductor devices are becoming minute year after year with an increase in high-integration of LSI. In order to form a desired circuit pattern on these semiconductor devices, a high-precision original pattern, such as a reticle or a photomask, is needed. The electron beam writing technology for writing or “drawing” a pattern herein essentially has excellent resolution, and therefore is used for manufacturing such high-precision original patterns.
FIG. 20 shows a conceptual diagram for explaining operations of a variable-shaped electron beam pattern writing apparatus. As shown in the figure, the variable-shaped electron beam pattern writing apparatus (EB (Electron beam) writing apparatus) includes two aperture plates. A first or “upper” aperture plate 410 has an opening or “hole” 411 in the shape of rectangle, for shaping an electron beam 442. This shape of the rectangular opening may also be a square, a rhombus, a rhomboid, etc. A second or “lower” aperture plate 420 has a variable shaping opening 421 for shaping the electron beam 442 having passed through the opening 411 of the first aperture plate 410 into a desired cross-section. The electron beam 442 that left a charge particle source 430 and has passed through the opening 411 of the first aperture plate 410 is deflected by a deflector to pass through part of the variable shaping opening 421 of the second aperture plate 420, and reaches a target object mounted on a stage which is continuously moving in one predetermined direction (e.g. X-axis direction). In other words, a rectangular shape capable of passing through both the opening 411 and the variable shaping opening 421 is written or “drawn” in a pattern writing area of a target object 440 mounted on the stage continuously moving in the X-axis direction. This method of writing or “forming” an arbitrary shape by letting beams pass through both the opening 411 and the variable shaping opening 421 is called the “variable shaping.”
To start performing such electron beam pattern writing, a layout of a semiconductor integrated circuit is designed first, and layout data (design data) for writing the design is created. Then, the layout data is converted into writing data to be input into an electron beam pattern writing apparatus. Further, the writing data is converted into internal data in EB writing apparatus to write a pattern.
With an increase in high-integration of LSI, it is requested to compress data amount because the amount of data processed by the EB writing apparatus is enormously increasing. Conventionally, when converting design data into writing data, the conversion is performed one by one for all the figures needed to be converted into writing data. For example, if two or more identical figures exist in one block, converting is performed for each of the figures. This method, however, has a problem that the processing time necessary for creating the writing data becomes enormous. Moreover, there is another problem that extremely large processing time is needed to transmit the created writing data to an electron beam pattern writing apparatus.
With the aim of reducing data amount, a method for creating writing data where data groups, each of which is composed of basic pattern data and location data for locating the basic pattern data, are continuously strung in one data file is disclosed, for example, in JP-A-05-29202.
It is possible to reduce data amount by creating data composed of data groups of basic pattern data and a plurality of pieces of location data defined one or more times for one basic pattern data as described in JP-A-05-29202. However, such data structure has little flexibility and it would require much time to reconfigure location data if it is needed because of intermingling of location data and pattern data.